Positron emission tomography scans in postchemotherapy seminoma patients with residual masses: a retrospective review from Indiana University Hospital.
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Diagnosis, Differential↗
Biomedical subjects
Mark Tann
Publications and source records attributed to Mark Tann.
Distribution of stage I lung cancer growth rates determined with serial volumetric CT measurements.
PURPOSE: To retrospectively determine the distribution of stage I lung cancer growth rates with serial volumetric computed tomographic (CT) measurements. MATERIALS AND METHODS: This study was institutional review board approved and HIPAA compliant. The informed consent requirement was waived. Patients (n = 149) with stage I lung cancer who underwent two pretreatment CT examinations 25 or more days apart were identified. At the first and last examinations, tumor perimeters were manually inscribed by using software tools and the cross-sectional area was calculated. To calculate tumor volume, the summed areas were multiplied by the section increment and a formula was applied to reduce partial volume effects. Doubling time (DT) was calculated by using the volume and interscanning interval. The percentages of tumors that would surpass volume increase thresholds of 5%-25% for detectable growth at different time intervals were calculated. Age at diagnosis was compared with the reciprocal of DT, time interval between CT examinations, and initial tumor volume by using Pearson correlation. P < .05 denoted statistical significance. RESULTS: Lung cancer was stage IA in 99 patients and stage IB in 50. Median patient age was 72 years, and median interscanning interval was 130 days. Median tumor volumes were 3000 and 6213 mm3 at the first and last examinations, respectively. Median DT was 207 days; 21 tumors did not increase in volume between examinations. The interscanning interval required for 90% of growing tumors to surpass the growth threshold ranged from 8 weeks (5% threshold) to 37 weeks (25% threshold). Fifty-three percent of growing tumors would surpass the 25% threshold at 8 weeks, and 95% would surpass it at 1 year. Age at diagnosis was negatively correlated with growth rate (P = .047); there was no correlation between growth rate and either age at diagnosis or interscanning interval. CONCLUSION: At serial volumetric CT measurements, there was wide variability in growth rates. Some biopsy-proved cancers decreased in volume between examinations.
Adult↗
Advances in alimentary tract imaging.
Advances in imaging techniques are changing the way radiologists undertake imaging of the gastrointestinal tract and their ability to answer questions posed by surgeons. In this paper we discuss the technological improvements of imaging studies that have occurred in the last few years and how these help to better diagnosing alimentary tract disease.
Digestive System↗
CT findings for postsurgical blind pouch of small bowel.
OBJECTIVE: Our objective was to define the CT criteria for blind pouches formed after enteric anastomosis. CONCLUSION: Familiarity with the CT appearance of blind pouches avoids the mistaking of these entities for bowel obstruction or abscesses.
Adult↗
Helical computed tomography accurately reports urinary stone composition using attenuation values: in vitro verification using high-resolution micro-computed tomography calibrated to fourier transform infrared microspectroscopy.
OBJECTIVES: To assess the ability of helical computed tomography (CT) to differentiate regions of known mineral composition in typical, heterogeneous urinary stones. Interest is substantial in the urologic community in using radiologic imaging to determine accurately the composition of urinary calculi. Recent advances in CT make this a viable prospect, but the heterogeneity of most stones is a complicating factor. METHODS: The ability of micro-CT (a high-resolution laboratory instrument) to identify the mineral composition of stones was confirmed by calibrating micro-CT attenuation values to pure mineral regions of sliced stones using infrared microspectroscopy. Intact human urinary stones were then analyzed by micro-CT, and regions-of-interest of pure mineral were correlated with identical regions-of-interest from quad slice multi-detector row helical CT images. With helical CT, narrow slice widths were used to decrease volume-averaging errors, and bone windows were used so that internal stone structure was visible. RESULTS: When stones were imaged using helical CT at narrow slice widths, mineral-specific regions-of-interest yielded nonoverlapping attenuation values for uric acid (566 to 632 Hounsfield units [HU]), struvite (862 to 944 HU), calcium oxalate (1416 to 1938 HU), and hydroxyapatite (2150 to 2461 HU). CONCLUSIONS: High resolution helical CT yields unique attenuation values for common types of stone mineral, but proper windowing is required to localize regions of homogeneity. The results of this in vitro study suggest that high-resolution helical CT may be able to identify stone composition at patient diagnosis.
Calcium Oxalate↗
Performance assessment of community-based physicians: evaluating the reliability and validity of a tool for determining CME needs.
PURPOSE: To evaluate the reliability, validity, and feasibility of the Physician Assessment in Medical Practice (PAMP) as a means of determining the CME needs of practicing, community-based physicians. METHOD: A group of 45 randomly selected community-based physicians (19 certified family physicians and 26 general practitioners) affiliated with the Department of Family Medicine at Bruce Rappaport Faculty of Medicine, Technion Institute of Technology, Haifa, Israel, volunteered to participate in the study, conducted in 1997. All participants took a ten-station, performance-based examination designed to closely represent the physicians' work settings. At each station, a different medical problem was presented by a standardized patient. Physician-candidates' performances were assessed by physician-examiners using global ratings. The following performance domains were assessed: information gathering, diagnosis and management plan, and communication skills. A CME needs assessment score was determined for each of the participants and a CME level to meet the needs of the physician was recommended. RESULTS: Overall reliability of the examination was high (.87), with domain reliabilities ranging from.76 to.87. Reliability of the examiners' judgments of the physicians' competence was.66. All the stations' validity scores were significant, and differences in performances between family physicians and general practitioners demonstrated construct validity of the test results. Overall, the cost of running the examination was U.S. $250 per physician-candidate. CONCLUSIONS: Using the PAMP to determine CME needs of community-based physicians was found to reliable, valid, and feasible, and the cost per physician-candidate was not excessive. Performance results provided indepth information for use by both the individual physician and providers of CME programs.
Adolescent↗
Volumetric growth rate of stage I lung cancer prior to treatment: serial CT scanning.
PURPOSE: To determine the range of growth rates of stage I lung cancers prior to treatment by using volumetric measurement at serial chest computed tomographic (CT) examinations. MATERIALS AND METHODS: The study population comprised 50 patients who underwent two CT examinations at 25-day or greater intervals. Tumor craniocaudal length and cross-sectional diameters and perimeters were used to volumetrically model each tumor in three ways (spherical, elliptical, perimeter). Volumes were compared by determining Pearson correlation coefficients. By using these volumes, tumor doubling time was determined for each patient. RESULTS: Volumes measured with all three methods were highly correlated. With the perimeter method, median doubling time was 181 days, with a very wide range. Eleven (22%) of 50 tumors had doubling times of 465 days or more. There was considerable overlap in doubling time between histologic subtypes. Assuming constant growth, only three (6%) of the 50 tumors would have been the size of a stage IA tumor for less than 1 year. CONCLUSION: Comparison of tumor volumes at serial CT examinations reveals a very wide range of growth rates. Some tumors grow so slowly that biopsy is required to prove they are malignant.
Adult↗
Disconnected pancreatic duct syndrome: imaging findings and therapeutic implications in 26 surgically corrected patients.
PURPOSE: The lack of ductal continuity between a viable pancreatic tissue and the gastrointestinal tract results in the disconnected pancreatic duct syndrome (DPDS). The purpose of our study is to describe accurately the imaging features of CT scanning and endoscopic retrograde pancreatography (ERCP) that define the DPDS. METHODS: We conducted a retrospective analysis of the computed tomography (CT) and ERCP examinations in 26 consecutive patients with surgically proven disconnected pancreatic ducts treated over a 5-year period at our institution. Two abdominal radiologists concurrently defined the imaging features (presence and size of fluid collection along the course of the pancreatic duct, upstream enhancing pancreatic parenchyma, and ERCP abnormalities) via consensus for both exams. Patient demographics, etiology of pancreatitis, surgical treatment, initial CT interpretation, and the delay between symptom onset to correct diagnosis were recorded. RESULTS: A discrete, intrapancreatic fluid collection (average size = 27 cm2 (range, 4-74 cm2) along the course of the main pancreatic duct with upstream viable pancreatic parenchyma was identified by CT in 26 cases. ERCP showed ductal obstruction at the level of the intrapancreatic fluid collection in all patients with extravasation of contrast in 14 (54%). All patients were treated by operation: 15 (58%) by internal drainage into a Roux-en-Y limb of jejunum and 11 (42%) by distal pancreatic resection. No prior CT interpretation correctly identified DPDS. The average delay between symptom onset and definitive diagnosis was 9.3 months (range, 3-36 months). CONCLUSIONS: A discrete intrapancreatic fluid collection along the expected course of the main pancreatic duct with viable upstream pancreatic parenchyma suggests the diagnosis of DPDS. ERCP findings of ductal obstruction at the level of this fluid collection with or without contrast extravasation confirm this diagnosis. Treatment is surgical and requires either internal drainage or distal pancreatic resection for complete resolution.
Adult↗
Computed tomography demonstration of lipomatous metaplasia of the left ventricle following myocardial infarction.
Replacement of myocardium by fat, particularly of the right ventricle, is often diagnosed as arrhythmogenic right ventricular dysplasia. At autopsy, however, 68% of scars associated with chronic ischemic heart disease have shown fatty metaplasia in the scar. Four patients with a past history of previous myocardial infarctions and computed tomography demonstration of fatty change in left ventricular regions of hypokinesis and infarction are presented. It is proposed that these findings represent ischemic fatty metaplasia, an alternative etiology of fatty tissue replacing myocardium.
Adipose Tissue↗